Photoinduced palladium-catalyzed 1,2-difunctionalization of olefins

Palladium-catalyzed cross-coupling reactions belong to the most important transformations for the construction of new C-C or C-heteroatom bonds. More recently, the photochemical activation of palladium complexes emerged as a key strategy to leverage palladium catalysis at room temperature beyond the scope of conventional cross-coupling chemistry. Herein, we report on the photoinduced, palladium-catalyzed 1,2-difunctionalization reaction of electron-rich olefins. Mechanistic experiments and computational studies reveal that this reaction proceeds via addition of an alkyl radical followed by a oxidation of a radical intermediate to access carbocation intermediates, which is inaccessible via classic thermal reaction conditions. The carbocation can then be applied to a variety of secondary C-C or C-heteroatom bond forming reactions. This strategy now allows a general approach towards densely functionalized unsymmetric 1,1-bis(heterocyclyl)alkanes.